Hi
I have a strange problem with a marantz cd65 MK2 SE. It has the TDA1541A chip set and a cdm4/19 it randomly stops playing. Anywhere on the disc could be a few second in to near the end. when it stops it runns through all the track numbers on the display then stops. on some occasions it has twitched the cd drawer. Since this i have taken out the mechanism cleaned and greased all little ball bearings bearings. previous to this i have also resurface the spindle plate that wears out. any idea and help would be great.
thanks
Tom
I have a strange problem with a marantz cd65 MK2 SE. It has the TDA1541A chip set and a cdm4/19 it randomly stops playing. Anywhere on the disc could be a few second in to near the end. when it stops it runns through all the track numbers on the display then stops. on some occasions it has twitched the cd drawer. Since this i have taken out the mechanism cleaned and greased all little ball bearings bearings. previous to this i have also resurface the spindle plate that wears out. any idea and help would be great.
thanks
Tom
Ideas... and they are only ideas... would be to check for dries, particularly in the PSU and on any components that run hot such as onboard regs, motor drive amps etc. The twitchy drawer might be a symptom of a twitchy rail and random uP resets. You have to start with the basics before jumping to conclusions.
Thanks for the reply.
Sorry I forgot to mention I have just replaced the PSU capacitors as one had died.
I shall have the PCB out and check for any lifted tracks and dry joints.
should I have reset the trim pots after doing this.
Sorry I forgot to mention I have just replaced the PSU capacitors as one had died.
I shall have the PCB out and check for any lifted tracks and dry joints.
should I have reset the trim pots after doing this.
Replacing PSU electroylitics shouldn't cause need to readjust anything. Does this player have the notorious 33uf cap under the RAFOC that causes intermittent problems ?
The actual laser head has a very small PCB with a few Surface mount components. everything else is on the main PCB I don't think there are any 33µf capacitors on the PCB lots of 47µf 25v and some of those blue axial philips. If its any help the Circuit diagram is attached
Tom
Tom
Attachments
Twitching drawer is an odd symptom. Perhaps the tray detect microswitch has an unreliable contact? Just a thought.
Note the MAB8441 also controls the drawer, and accepts the signal from the tray detect switch.
Note the MAB8441 also controls the drawer, and accepts the signal from the tray detect switch.
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I had exactly the same symptom in a Marantz DR6000. ( very similar internally to your machine I think) After searching for a cause I found that it was due to overheating - but I did not isolate the guilty part as there are a number of hot parts. However I cured the problem by inserting a small computor fan in one end of the case.
You could maybe check if this is your problem by running the cd player in a cool place to see if that helps.
Don
You could maybe check if this is your problem by running the cd player in a cool place to see if that helps.
Don
I did notice it gets hot around the power supply and transformer around 50 Deg C particularly the voltage regulator attached to the heat sink/shield but I thought this was acceptable temp. tomorrow Ill check the switch out (close to the PSU but not that close) and check the traces and see if i can check capacitors.
C2546 bottom left which is a 47uf here. The original Philips versions used 33uf.
Its the drawer thing that is odd though, and that points to maybe a rail dropping out momentarily and causing the uP or SYCON to reset. Its far from unheard of for 78/79 etc regs to be troublesome. Might be worth carefully monitoring the rails with a scope and DVM to see if they are really steady.
Ok i've got to get to the rails I'll check that capacitor what is SYCON I'm guessing at SYstem CONtroller; the MC8805LB marked control-µP doc-5. The try detection switch is shown on doc-4 it's the same micro controller shown in the servo circuit/focus/radial drive diagram doc-3.
I've uploaded the rest of the circuit diagrams.
Unfortunately I don't have a scope it's one of those things I can't yet afford.
I've uploaded the rest of the circuit diagrams.
Unfortunately I don't have a scope it's one of those things I can't yet afford.
Attachments
Yep, SYSCON is system control 🙂
It does sounds an uncommon or "one off" type of fault with the drawer doing what it does but as with most faults, dries and PSU issues are favourite. Obviously make sure any mechanical issues are attended to first such as checking and cleaning leaf/micro switches. Any large IC's are the very last things to even point a finger at, it will be something else.
It does sounds an uncommon or "one off" type of fault with the drawer doing what it does but as with most faults, dries and PSU issues are favourite. Obviously make sure any mechanical issues are attended to first such as checking and cleaning leaf/micro switches. Any large IC's are the very last things to even point a finger at, it will be something else.
well I't seams it's a problem bought on by heat. yesterday it was in a cabinet with closed in back though there was a fair amount of space round it. It's now been plying faultless for hours out in the open. looking at the psu how tight it is and the temperature in there and from what has been said i would hazard a guess at a voltage regulator or capacitor. when i had the PCB out I visually checked for any obvious problems like lifted tracks and dry joints. I'll probably replace some of the 47µF caps anyway esp the one mentioned.
I might be wrong but, from memory, the original cap doesn't cause problems, but an inappropriate replacement can. A cap with very low ESR shouldn't be used there. Nor should one be used immediately following a voltage regulator, by the way.
These machines sound good but they're flimsy and awkward to work on. Because of the weight of the transformer fixed to the circuit board, it tends to flex a lot during handling. If you need to take it apart again, check the traces and soldering around the transformer for cracks.
They aren't safe in the post for that reason. If the machine flops onto its back, the transformer screws rip out and total carnage ensues
Philips plastic declined sharply in quality IMO. Good heavy transformer though.
when i did the psu I replaced the main caps with panasonic FC capacitors after the regulators with panasonic FR so they have quite low ESR would a the FC or something with even less better after the reg?
Its still all guesswork but from what you say replacing the 78/79 regs might be worthwhile. Unless you can observe a problem (scope which you haven't access too) then its a case of second guessing the issue.
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